The present invention relates to a silver halide photographic photosensitive material and more particularly, to an antistatic back coat layer.
In silver halide photographic photosensitive materials, a film, a paper and the like are used as a base, but these are low in electrical conductivity and have various problems.
One of these problems is that when a coating solution containing silver halide is coated on a film or a paper, this is coated at a high speed by a coater, but the film or paper is electrically charged while being rubbed with a roller and if discharging occurs, the silver halide is fogged (static fogging). If the back coat layer is enhanced in electrical conductivity and is imparted with antistatic properties, since the back coat layer is usually coated before coating of silver halide emulsion, this back coat layer causes, through the base, improvement of antistatic properties of the surface to be coated with emulsion which is opposite side to the back coat side and as a result, the static fogging can be inhibited.
Another problem is that when users use photosensitive materials, if these are statically charged, dusts stick to the photosensitive materials and often cause formation of undesirable images such as pin holes during the courses of exposure and photographic treatments and furthermore, may cause adhesion of the photosensitive materials to each other to deteriorate operability. Further problem is that these photosensitive materials discharge through hands.
It is important that photosensitive materials must have good antistatic properties before and after the treatment such as development, fixation and water washing.
Japanese Patent Kokai Nos. 56-92535 and 61-174542 disclose that an antistatic layer is provided between a back coat layer and a base to increase antistatic properties through this layer and besides, an aziridine hardener is used for improvement of adhesion between the antistatic layer and the back coat layer. However, the aziridine hardener causes eruption on the skin and use thereof is not desired for safety and sanitary reasons In addition, there is the problem that since an antistatic layer is provided between a base and the back coat layer, adhesion of the back coat layer is not sufficient and besides, dryness is poor